Personally, I'm seeing some dramatic shifts for some of the results I track. One site that appeared nuked by Penguin has returned. However a lot of utter junk is still there, including some hacked sites. Deeper in the results there is a very dramatic shift to junk urls with scraped postings.
I'd say an update rolled out affecting penguin. But I did say it before and was wrong then. Just like the first iteration (if in fact there has been a second) much of what I'm seeing is a surfacing of some junk tactics that really shouldn't work, but suddenly do.